Mr. O’Neill, now a research fellow at Bruegel, a European think tank, gained fame for coining the term “BRICS” to refer to Brazil, Russia, India, China and South Africa.

He’s been a proponent of a view of the world in which economic power is shifting from the U.S. and Europe to fast-growing developing economies.

Now, Mr. O’Neill is calling for an overhaul to the current system of global pow-wows to reflect these realities. In the paper, Mr. O’Neill and co-author Alessio Terzi argue the G-20 is too unwieldy to take decisive action.

Part of the problem, Mr. O’Neill argues, is that the G-20 contains too many voices. Launched in 2008, the group was supposed to be more diverse and initially it had some success in coordinating a world-wide response to the financial crisis.

But now, with members ranging from the U.S. to Indonesia and Turkey, it is “too cumbersome to be truly effective,” Mr. O’Neill writes.

Instead, world leaders should consider an overhaul of the Group of Seven – the club of developed nations that used to coordinate global policy. Rather than have Italy, France and Germany in that grouping, the European Union would get one seat, freeing up space for China and another fast-rising economy, Mr. O’Neill suggests.

Mr. O’Neill uses data to underscore the point. China’s economy is today four times the size of Italy’s, and this could rise to seven times by 2020. Canada, another G-7 member, is even smaller than Italy.

Italy’s status as a large democracy “might give it some vague justification in a lesser and lesser important G-7 Group,” Mr. O’Neill writes, “but in terms of an optimal world economy and its governance, this is hardly a reasonable stance.”

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